Ismail Yuksek

LPV gain-scheduling controller design for a non-linear quarter-vehicle active suspension system

There always exists a conflict between ride comfort and suspension deflection performances during the vibration control of suspension systems. Active suspension control systems, which are designed by linear methods, can only serve as a trade-off between these conflicting performance criteria. Both performance objectives can only be accomplished at the same time by using a nonlinear controller. This paper addresses the non-linear induced L2 control of an active suspension system, which contains non-linear spring and damper elements. The design method is based on the linear parameter varying (LPV) model of the system. The proposed method utilizes the bilinear damping characteristic, stiffening spring characteristic when the suspension deflection approaches the structural limits, mass variations and parameter-dependent weighting filters. Simulation studies both in time and frequency domain demonstrate that the active suspension system controlled by the proposed method always guarantees an agreement between acceleration (comfort) and suspension deflection magnitudes together with a high ride performance.

Application of Fuzzy PID Control to Cluster Control of Viaduct Road Vibrations

Distributed parameter systems have infinite-degrees of freedom. Algorithms for vibration control of these systems have provided satisfactory results for low-frequency ranges but these approaches may cause spillover and undesired conditions at high-frequency ranges resulting in unsatisfactory control performance. In this study, the application of cluster control on viaduct roads composed of flat parts is introduced. Cluster control consists of three stages: sensing, actuation and control of desired mode groups using a control method. Sensing and actuation of mode groups are introduced separately. The grouping and sensing of mode groups are realized by using Finite Element Analysis. Various control architectures, of which the most popular ones are classical PID controllers, have been suggested to apply cluster control for vibrating structures. In this study, a Mamdani-type fuzzy PID controller with two input and two output is suggested and the system responses, whose dynamics are gathered from a scaled size of a viaduct road, are collected for proposed fuzzy-PID and sliding mode controllers. Analysis of the performance of cluster control along with the individual effects of the controller parameters on system frequency response is discussed and presented.

LPV Model Based Gain-scheduling Controller for a Full Vehicle Active Suspension System

This article addresses the design of a gain-scheduling type nonlinear controller for a full-vehicle active suspension system. The proposed method is based on a Linear Parameter Varying (LPV) model of the system. In this model, the variations in suspension deflection and mass are chosen as the scheduling parameters. During the simulations, the full-vehicle system that is controlled by the proposed method is tested with different road profiles, having high and low bumps, hollows and combinations of the two. The simulation results demonstrate that the proposed method successfully maximizes the ride comfort when suspension deflection is far away from the structural limits and minimizes the suspension deflection by changing its behavior when the suspension limits are reached.

Adaptive control of structures with MR damper

In this study, an adaptive control scheme is designed for vibration isolation of SDOF structural system using a semi-active MR (magnetorheological) damper. The main goal of using a MR damper system is for structural protection against earthquake excitation and wind loading. A structural system excited by an earthquake and controlled by using MR damper is modeled as a semi-active controlled, seismically excited and a nonlinear system with SDOF. A nonlinear observer is used to estimate of the unmeasurable internal state variable. Unknown parameters of MR damper are obtained by adaptation rules. The necessary input voltage to MR damper so as to generate desired damping force is derived by the adaptive control. Finally, response of semi-actively controlled building is obtained by simulation.

Lumped parameter identification of a quarter car test rig

Quarter car model is a simple and widely used mathematical model to analyze the vibration and control problem of vehicles. In this study, a quarter car test rig is modeled as a lumped parameter system. Model parameters of the system are determined by measurements and experiments. Forced vibration method is used to identify the stiffness and damping parameters of the lumped model. A modal shaker is used to generate the road input in the test rig. The accelerations of the road input, sprung and unsprung masses are measured by piezoelectric accelerometers. The frequency response functions are obtained by using acceleration data. The identified parameters of the test rig are adjusted by comparing the experimental and simulation results.

Natural frequencies of a flat viaduct road part simply supported on two ends

Viaduct roads have wide application in big cities with high traffic loads, in order to decrease traffic density and to connect subways to highways. Viaduct roads are constructed using steel structures instead of concrete ones in areas of earthquake risks. The low weight of steel structures however causes problems such as vibration and noise. There is increasing demand especially in populated areas to suppress vibration and noise on highway roads for reducing noise-related environmental pollution.In this study, bending vibrations of rectangular plate viaduct roads, which are supported by six fixed elements of rectangular cross-sectional elements are considered. Natural frequencies are obtained using the Rayleigh-Ritz technique, finite elements analysis, experimentally and neural networks (NN).

Modal filtering for active vibration control of high-rise structures using PVDF sensors

This study presents a modal filtering approach to separate the structural modes of a high-rise structure using shaped film sensors. A building like model structure is constructed to realize the proposed model filtering approach. Since it is difficult to define a modal shape function for discrete parameter structures, analytical and experimental approaches are discussed to determine the shape of the sensor. In the experiment the first structural mode of the high-rise structure is successfully filtered and robustness of the sensor output against parameter uncertainty is also tested.